Too few ward nurses linked to longer hospital stay, readmission, and risk of death

Employing too few permanent nurses on hospital wards is linked to longer inpatient stays, readmissions, patient deaths, and ultimately costs more in lives and money, finds a long-term study published online in the journal BMJ Quality & Safety.

Redressing the balance is cost-effective, saving an estimated £4,728 for each year of healthy life gained per patient, but not if temporary agency staff are used to plug the gaps, the findings indicate.

Inadvertent understaffing–through unfilled vacancies–or deliberate–through cost-cutting measures of ward nurses risks harming hospital patients, and is a key contributor to nursing recruitment and retention issues, say the researchers.

Much of the existing research on the impact of nursing staff-to-patient ratio is cross-sectional and so is of limited use in determining causal factors, they add.

To find out if investing in higher nurse staffing levels to offset understaffing would be cost-effective, they set out to estimate the associations between registered nurse and health care assistant staffing levels and risk of patient deaths, readmissions, and length of stay in acute adult inpatient wards.

They drew on data provided by four NHS hospital trusts with diverse nurse staffing levels, sizes, teaching status, serving diverse local populations in England. Three of the trusts provided acute inpatient services, predominantly from single hospital sites, and the fourth provided inpatient services across four sites within one city.

The data were derived from electronic health care records and staffing rosters and spanned the period April 2015 to March 2020 for a total of 626,313 patients in 185 different acute care wards.

Two main nursing team roles were included in the study: registered nurses (RNs) who have completed university degree level training and are registered with the profession’s regulator; and nursing support staff (such as health care assistants) who don’t have this level of training and who are largely unregulated.

The incremental cost-effectiveness of eliminating the understaffing of these two roles was estimated from the costs and consequences of moving from the observed staffing shortfall averaged over the study period to the planned staffing level.

Patients spent an average of eight days on the ward. Over the first five days of their inpatient stay, patients were provided with a daily average of just over five hours of care from RNs and just under three hours of care from nursing support staff.

The calculations showed that patients on wards understaffed by RNs were more likely to die (5% vs. 4% for those with adequate RN staffing levels), to be readmitted (15% vs. 14%), and to stay in hospital longer (eight days vs. five days), with similar figures for inadequate numbers of nursing support staff.

Patients who experienced understaffing received an average care shortfall of one hour nine minutes/day in the first five days, while those who didn’t experience understaffing received an average of three hours 22 minutes of care above the ward average.

During the study period, 31,885 patients died. Each day a patient experienced RN understaffing (staffing below the ward average) during the first five days of their stay, the risks of death and readmission within 30 days increased by 8% and 1%, respectively. When all five days after admission were understaffed, length of stay increased by 69%.

Days of nursing support understaffing were also associated with similar increases in the risks of death and length of stay within 30 days: 7% and 61%, respectively. But the risk of readmission within 30 days fell by 0.6%.

The estimated total cost of providing care for the 626,313 adults included in the study amounted to £2,613,385,125, or £4,173 per admission.

The researchers calculated that eliminating understaffing of both nursing roles would cost an additional £197 per patient admission, avoiding 6,527 of the 31,885 deaths during the study period and gaining 44,483 years of life in good health.

This equates to an additional staff cost of £2,778 per healthy year of life, and £2,685 if reduced sick leave and averted readmissions are taken into account. But accounting for reduced length of stay amounts to savings of £4,728 per additional year of healthy life gained—an overall cost saving from increasing staffing levels.

If agency staff are used to eliminate understaffing instead, staff costs for each additional healthy year of life gained were higher, ranging from £7,320 to £14,639.

“The findings give no indication that it makes rational economic sense to target efforts to rectify low staffing only on the most acute patients. Not only is this logistically difficult for patients whose acuity is emergent (occurring while on a general ward), it also gives much less benefit at a considerably higher cost per unit improvement in outcome,” explain the researchers.

“Steps to address low staffing for the general (lower acuity) population are likely to benefit high-acuity patients as well, in so far as they are in the same units, whereas the opposite is unlikely to occur if interventions are targeted on high-acuity patients in high-acuity units,” they add.

This is an observational study, and as such, no firm conclusions can be drawn about cause and effect. And the researchers acknowledge that the data came exclusively from hospitals in the English NHS, so may not be more widely applicable. Understaffing was also judged relative to ward norms rather than a validated assessment of staffing need.

But the researchers conclude, “When considering alternative policy strategies, this study indicates the importance of prioritizing investment in RNs employed on wards over support staff, as well as showing there are no shortcuts to employing enough RNs, as using temporary staff is more costly and less effective.”